In making frameworks by joining of beams has previously a manufacturing method been used where non surface treated beams are joined by riveting. A surface coating has been applied to the framework when the beams have been joined. In a modernised manufacturing process the procedure of manufacturing has been altered so that the beams are coated prior to the joining of the beams. A result of this manufacturing process is that a surface coated layer is positioned between the head of the rivet and the beam. The rivet is deformed by subjecting it to a substantial pressure in the procedure of joining of the beams by the rivet. In using this process there is a high risk of damaging the underlying layer of surface coating, resulting in surface corrosion and an initial risk of corrosion of the beam. The damage occurs due to the facts that the portion of the head of the rivet that is in contact with the surface coating is shaped with a sharp edge and that said portion of the head is deformed, whereupon a displacement of material under substantial pressure occurs in the radial direction of the rivet. The sharp edge may easily harm the surface coating and said displacement of the material may result surface tension in the coating and that the coating is partly removed.